OK. I need eagle eyes and some lateral thinking here. Having completed my layout, the final DRC check showed two Track to Pad errors as shown below.  For starters I deleted both tracks, and sure enough both errors cleared. As you can see though, both tracks and the pads that they were connected to are on the same net, and the error crosses are away from any visible pads so there should be no issue there.  I then started to replace one of the tracks, with the following result.  So where is the phantom pad? Starting the new track from the oval NEUTRAL pad, as I move the end of the track to the right or left the error cross moves horizontally along the centre (where the red dotted line of the track cursor is in the image above) of the grid square that surrounds the error cross. If I take the end of the track outside that square to the right, the error clears, and to the left it moves to become a genuine error on the U3_3 pad. Move it up and the error cross stays on the centre line. Move it down below the centre line of the grid square, and it clears.  So what's on the grid square horizontal centre line that the DRC check thinks is a pad? Any suggestions welcome.